Electrical test probes with a contact element, methods of making and using the same

Abstract

Disclosed herein are electrical test probes and methods for making the same. In one embodiment, an electrical test probe comprises: a barrel, a plunger, a contact element, and a spring. The barrel comprises a contact area defined by a stop engagement and an opening at a first end of the barrel. The plunger is slidably disposed through the opening, the contact element, and the contact area. The plunger comprises a tip and a stop protrusion with a plunger extension extending therebetween. The contact element is disposed in the contact area, between the barrel and the plunger. The spring is in operational engagement with the plunger.

1. An electrical test probe, comprising:
 a barrel comprising an opening at a first end of the barrel, a barrel portion, a stop engagement located between the opening and the barrel portion, and a contact area defined by the opening and the stop engagement; 
 a plunger slidably disposed through the opening and the contact area, the plunger comprising a tip and a stop protrusion with a plunger extension extending there between, wherein the stop protrusion is located in the barrel portion; 
 a contact element disposed in the contact area, between the barrel and the plunger, wherein the plunger is slidably disposed through and in physical contact with the contact element; and 
 a spring in operational engagement with the plunger. 
 
     
     
       2. The probe of  claim 1 , wherein the contact element is a coiled element comprising a plunger extension contact portion formed by a reduced diameter portion of the coiled element. 
     
     
       3. The probe of  claim 1 , wherein the contact element is disposed in continuous physical contact with the barrel and the plunger. 
     
     
       4. The probe of  claim 1 , wherein the plunger further comprises a connector disposed between the stop protrusion and a second protrusion, wherein the barrel further comprises a second engagement, and wherein the second protrusion is disposed on a side of the second engagement opposite the stop engagement. 
     
     
       5. The probe of  claim 1 , further comprising a transfer plunger extending through an end of the barrel opposite the opening. 
     
     
       6. The probe of  claim 1 , further comprising a resistance of less than or equal to about 50 milliohms. 
     
     
       7. The probe of  claim 6 , wherein the resistance is less than or equal to about 25 milliohms. 
     
     
       8. The probe of  claim 1 , wherein the contact element further comprises a coating of an electrically conductive material. 
     
     
       9. The probe of  claim 8 , wherein the electrically conductive material is selected from a group consisting of gold, silver, platinum, palladium, cobalt, nickel, and combinations comprising at least one of the foregoing electrically conductive materials. 
     
     
       10. The probe of  claim 9 , wherein the electrically conductive material is selected from the group consisting of platinum, palladium, cobalt, and combinations comprising at least one of the foregoing electrically conductive materials. 
     
     
       11. The probe of  claim 1 , wherein the contact element further comprises less than or equal to about 10 turns. 
     
     
       12. An electrical test probe, comprising:
 a barrel comprising an opening at a first end of the barrel, a barrel portion, a stop engagement located between the opening and the barrel portion, and a contact area defined by the opening and the stop engagement; 
 a plunger slidably disposed through the opening and the contact area, the plunger comprising a tip and a stop protrusion with a plunger extension extending there between, wherein the stop protrusion is located in the barrel portion; 
 an electrically conductive, coiled contact element disposed in the contact area, between the barrel and the plunger, wherein the plunger is slidably disposed through the contact element wherein the contact element creates a signal path between the barrel and the plunger; and 
 a spring in operational engagement with the plunger. 
 
     
     
       13. A method for operating an electrical test probe, comprising:
 disposing a test probe in physical contact with a device to be tested, wherein the test probe comprises 
 a barrel comprising an opening at a first end of the barrel, a barrel portion, a stop engagement located between the opening and the barrel portion, and a contact area defined by the opening and the stop engagement; 
 a plunger slidably disposed through the opening and the contact area, the plunger comprising a tip and a stop protrusion with a plunger extension extending there between, wherein the stop protrusion is located in the barrel portion; and 
 a contact element disposed in the contact area, between the barrel and the plunger, wherein the plunger is slidably disposed through the contact element wherein the contact element creates a signal path between the barrel and the plunger; 
 passing an electrical signal from the tip through the plunger and to the barrel; and 
 repeating passing the electrical signal from the tip through the plunger and to the barrel, wherein the electrical signal passes from the plunger to the barrel in the contact area. 
 
     
     
       14. An electrical test probe, comprising:
 a barrel comprising a contact area defined by a first engagement and a second engagement, and comprising a barrel portion, wherein the first engagement is disposed near a first end of the barrel, and wherein the second engagement is located between the contact area and the barrel portion; 
 a plunger slidably disposed through the opening and the contact area, the plunger comprising a tip and a stop protrusion with a plunger extension extending there between, wherein the stop protrusion is located in the barrel portion; 
 a contact element disposed in the contact area, between the barrel and the plunger extension, wherein the plunger is slidably disposed through and in physical contact with the contact element; and 
 a spring in operational engagement with the plunger. 
 
     
     
       15. The probe of  claim 14 , further comprising a resistance of less than or equal to about 50 milliohms. 
     
     
       16. The probe of  claim 14 , wherein the contact element further comprises a coating of an electrically conductive material selected from a group consisting of gold, silver, platinum, palladium, cobalt, nickel, and combinations comprising at least one of the foregoing electrically conductive materials. 
     
     
       17. The probe of  claim 16 , wherein the electrically conductive material is selected from the group consisting of platinum, palladium, cobalt, and combinations comprising at least one of the foregoing electrically conductive materials. 
     
     
       18. The probe of  claim 14 , wherein the contact element further comprises less than or equal to about 10 turns. 
     
     
       19. The probe of  claim 14 , wherein the physical contact is continuous physical contact with the plunger and the barrel. 
     
     
       20. The probe of  claim 1 , wherein the contact element is inhibited from moving with the plunger by the opening and the stop engagement. 
     
     
       21. An electrical test probe, comprising:
 a barrel comprising an opening at a first end of the barrel, a barrel portion, a stop engagement located between the opening and the barrel portion, and a contact area defined by the opening and the stop engagement; 
 a plunger slidably disposed through the opening and the contact area, the plunger comprising a tip and a plunger section with a plunger extension extending therebetween, wherein the plunger section is located in the barrel portion; 
 a contact element disposed in the contact area, between the barrel and the plunger, wherein the contact element is in physical contact with the plunger extension and the barrel, and wherein the plunger is slidably disposed through the contact element such that, in use, the plunger extension can slide through the contact element into the barrel portion; and 
 a spring in operational engagement with the plunger.